Part of the appeal, of course, is Yale’s fabulous collection of art. No one is going to fail to notice that. But I’m going to ignore it. I just want to talk about the virtues of the Gallery’s architecture. That, too, is part of what makes it such a winner.

There are lessons here for any art museum that wants to do a good job. Yale gets at least five things right:

■ It’s free. There’s no entry fee, no ID check, no fuss. You just walk in as if you owned the place. There’s even a welcoming, newsy electronic sign out on the sidewalk that reminds you that the Gallery is open to the public. That’s a nice populist touch that says the place isn’t just for Yalies.

You might think this isn’t a very architectural issue. But how you access a building is always a key to its architecture. Here, it makes a huge difference.

When a museum is free, you feel a sense of membership that you don’t feel when you have to pay up. It’s not the money that matters. It’s the role you’re asked to play. It’s the difference between feeling like a proprietor and feeling like a customer.

At Yale I spent a couple of hours with the Gallery’s director, Jock Reynolds, who used to run the Addison Gallery in Andover. We toured the museum, then we went out and crossed the street for cappuccinos, then we wandered back into the museum. There was a sense of ease and welcome you can’t get any other way.

If you’re passing by and have a few minutes, you can stop by the Gallery and commune with a favorite work of art. You’re not likely to do that if it’s going to involve the least bother about admission.

■ It doesn’t confront you with commerce. There’s no museum shop filled with silly mementos, no pricey cafe for bored visitors. The message is that this place is about art. The first thing you see when you enter, in the current installation, is a cluster of dark, silent figures by sculptor Judith Shea. It keynotes your visit. By way of contrast, think of, say, the Museum of Modern Art in New York, where the entry lobby looks and sounds like an airline terminal.

■ It’s an integral part of something larger. Yale gets away without a shop or cafe, and one very good reason it can is that the Gallery isn’t an isolated entity. It’s part of busy Chapel Street in New Haven, just one element in the larger activity of the city. Art is often presented as if it should be approached with hushed awe. At Yale, the message is that art is neither a sacred activity nor a bastion of academia. It’s part of life.

■ It’s made of more than one building. The Gallery occupies a block-and-a-half row of what were at one time three separate buildings, now joined into one connected complex. One is a modernist classic of 1953 by a famous architect, Louis Kahn. One is a bulky work of 1928 that looks like a medieval castle. And a third, built in the Gothic style in 1866, resembles a chapel. The three have been home to different uses at different times.

Viewed from outside, the buildings can be seen as a collection of pieces of architecture that become a metaphor for the diverse collection of artworks to be found inside. The buildings embody a democratic variety of tastes and cultures. By contrast, a single big museum, built all at once, can feel slightly authoritarian. Yale’s architecture reminds us that cities and art collections are both assembled from individual initiatives and from different eras, and that they’re always in process of change.

The fact that the Gallery fits so well into such a variety of buildings reminds you of another architectural truth, which is that form doesn’t necessarily follow function. Any kind or shape of building can be turned into a fine museum, whether it was once a palace like the Louvre in Paris or a printing plant for cereal boxes like Dia:Beacon in upstate New York. And when you put art into a building that was built for some entirely different use, there’s often a slight sense of misfit, an awareness of new wine in an old bottle, that adds a frisson to your experience.

■ It’s full of memorable interiors. Because of the variety of the original buildings, there’s a range of distinctive indoor spaces. Some spaces feel like churches, some feel more like baronial halls, and some are crisply modernist. Many are rich in color and traditional detailing. There are high skylighted spaces, spaces with long views out over the campus, and spaces that are intimate and dark. Traditional architectural details like classical columns and arches are sometimes preserved in otherwise modernized spaces, where they hang around like visitors from the past.

Elizabeth Felicella, 2012

A view of the sculpture terrace.

Almost everywhere, the artworks are given memorable places they can inhabit. To appreciate what that means, you have to remember that placelessness is often a deliberate goal for designers of art museums. You achieve it by making totally anonymous space, with white walls and luminous white ceilings and a complete lack of architectural detail. When paintings, say, are hung in such spaces, they always remind me of digital images projected on screens. They haven’t been given an architectural place to inhabit, but merely float in whiteness. Lacking such a context, they have nothing to relate to except one another. They’re like well-dressed guests at a party who stand around trading comments about each other’s clothes.

Some art is right for placeless space, and there’s some of it at Yale. But it never becomes monotonous, because it’s just one choice in a rich spatial menu. Among so many options, a curator can find the right setting for any kind of art.

Those are some of the virtues that make the Yale Art Gallery an architectural winner. Credit goes to director Reynolds and a New York firm of architects known as Ennead. I realize, of course, that not every museum has the same opportunities as Yale, starting with the reported $135 million budget, the site, and the mix of existing buildings. But Yale is worth keeping in mind as one model of getting just about everything right.

Yale makes me think of one other point. In architectural history, very often, the greatest works are created at the end, not the beginning, of a cultural cycle. Such architecture is motivated by a doomed effort to arrest the decline of a culture by erecting monuments to it.

Today we’re building art museums like crazy. Like our medieval predecessors in their cathedrals, we in our museums gather to worship icons we may not fully understand. According to the American Alliance of Museums, there are now 3,700 art museums in the United States, more than 1,100 of them having opened since 1970.

Why the surge in art museums? Is all this solid brick and mortar, perhaps, a half-conscious reaction against an oncoming tsunami of digitization? Will the world of electronic images make the place-specific museum obsolete?

I have no idea. But while we wait to find out, I recommend a visit to the Yale Art Gallery.

Robert Campbell, the Globe’s architecture critic, can be reached at camglobe@aol.com.